For example, an electric junction box installed in an engine room of a vehicle has connection parts of a wiring harness, electric parts such as a relay or fuse, and electric component such as an electronic control unit. It is required to keep liquid such as water away from all parts of the electric junction box when the vehicle runs in the rain or the engine room is washed with high-pressure. For this reason, the electric junction box is constructed with a waterproofed box main body receiving the electric parts and the like, and a waterproofed cover for covering an upper opening of the box main body. The electric junction box has a function as a waterproof box.
For the waterproof box, various waterproof types are known. For example, one type is waterproofed by sandwiching a packing between a waterproof structure arranged in the box main body and a waterproof structure arranged in the cover (see Patent Document 1). Further, another type is waterproofed by overlapping the waterproof structure of the box main body with the waterproof structure of the cover without using the packing (see Patent Document 2).
In the waterproof box of type using the packing, since the packing sandwiched between the waterproof structures covers a gap, waterproof performance can be increased. However, there is a problem such that the parts of the packing are increased, and as a result costs are increased. Furthermore, process for installing the packing is increased. For this reason, in recent years, the waterproof box of type not using the packing is used.
The waterproof box of type not using the packing disclosed in the Patent Document 2 includes a box main body having an upper opening and a cover for covering the upper opening of the box main body. The waterproof box is waterproofed by overlapping waterproof structures which are provided in a box body and a cover joint respectively. More specifically, the box main body side waterproof structure has a circular waterproof projection arranged around the tip of the peripheral wall of the box main body. The cover side waterproof structure has a circular waterproof dent arranged around the tip of the cover peripheral wall of the cover.
In the above configuration and construction, the cover is arranged in the upper side of the upper opening of the box main body. And then, the cover is moved straight down, and the waterproof structures are overlapped. At this time, the waterproof projection is inserted in the waterproof dent. Further, a main body lock arranged in the waterproof structure of the box main body is locked on a U-shaped cover lock arranged in the cover waterproof structure. Thereby the box main body and the cover are locked, and become the locked state. The main body lock and the cover lock are provided in at least two positions which is located at the right and left sides of the waterproof box (or at the back and forth sides thereof). The two positions are separately located each other.